1993 BMW E31 850 V12 trials and tribulations - Our Shed

By: Guy Allen

Date: 10.04.2022

Rogue cooling systems, tired pumps and mobile painters - it's all happening in Guido's shed

You may recall last time we spoke about the mighty BMW 850Ci, I mentioned it had an unfortunate habit of blowing hot air on the driver side of the cabin, and cold for the passenger, when you had everything set for cold. That’s really no fun on a hot day and I optimistically assumed that fitting a new HVAC valve (essentially a controller for some of the prime mixing duties) would solve the problem. It hasn’t.

A few niggles have appeared

This, I suspect, means we’re going to have to take a more in-depth look at the heating/ cooling system, which is spectacularly complex. In addition to the HVAC, there’s a solid-state controller, plus 10 (yep…count them) stepper motors. There is however a good guide or manual available, all 40-odd pages of it!

While all this was being investigated, we shouted the Bimmer V12 a service through young Rhys at RPM Auto Tech in sunny Melbourne. Not surprisingly in a car this age, we tripped over a few other issues. The coolant pump is looking suspect, as are a bunch of front-end bushes. No problem – all the gear is ordered and we’ll sort that when it arrives.

The car is actually steering okay, though it will be interesting to have it just that little sharper.

In the midst of all this, we finally completed one little job that had been irritating the hell out of muggins. Some time ago we had a cover on the passenger-side pop-up headlight detach and jump ship. That was in the middle of the night, on a freeway, with a truck up my clacker. So there was no hope of pulling up and finding the thing.

My web search for replacements turned up one new ‘lid’ plus a used pair – so, feeling pessimistic that day I bought the lot. None of them matched the car, though the new one in black primer looked better than nothing.

Eventually I hauled in a mobile painter (Paul the Painter, he’s on Faceplant), who set up shop to tackle the three headlight covers, and another job on my Honda Blackbird motorcycle. Just as an aside, I’ve got into the habit of bundling a few jobs together for these folk, as it makes their visit well worthwhile.

Anyway, some hours later, we had a fresh-looking headlight cover or three, one of which was popped into place.

Next on the list is wheels. On the right day I quite like the ROH 19-inch rims that are on it at the moment but have two issues with them. The first is they’re so distant from the original rims that they hold back the value of the car; The second is super-lowprofile tyres are very prone to punctures and mud-wrestling a spare and a jack on the side of the road is not my idea of having a good time.

A Saturn 5 rocket is less complex

Original rims for these things are like the proverbial hens’ teeth, unless you get them from the USA – then the combination of the exchange rate and shipping makes them prohibitively expensive.

Option two is to find something locally that works, and that’s what I’ve done. It’s a set of Style 66 BMW M-branded wheels, as fitted to my E39 540 M-sport. They’re a ten-spoke 17-inch rim, in offset sizes with eight-inchers on the front and nine on the rear.

Original hoops on the E39

A set of five (three fronts and two rear) popped up online at $1500 and they should do nicely. The catch is they have varying degrees of gravel-rash and will need refurbishing and then of course fresh rubber. I’m aiming for the same rolling diameter, which means we’ll end up with a substantially taller profile rubber that in turn should provide a slightly smoother ride.

That’s enough to keep us occupied for the time being…

 New old ones for the 850

From Unique Cars #452, Feb 2022

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